JP2003117271A - Sewing machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sewing machine miniaturized in cam, in which the cams are changed-over and at least one cam is exchanged. SOLUTION: The cam device 40 of a zigzag sewing machine 30 includes a groove cam 41 and a rib cam 42. The rib cam 42 has a rib 77 on an outer periphery and an outer diameter may be reduced. In the cam device 40, a needle moving cam arm 45 is moved forward and backward so that the groove cam 41 and the rib cam 42 are changed-over. A stitch pattern is changed by changing-over the cams. The rib cam with a smaller diameter is fixed to an internal side, the groove cam with a larger diameter is arranged at an external side and they are exchanged.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sewing machine such as a zigzag stitch sewing machine having a needle swinging mechanism for swinging a vertically moving needle.

[0002]

2. Description of the Related Art Conventionally, in a zigzag stitch sewing machine,
In order to form a needle swing pattern such as a zigzag stitch, a needle swinging device that internally reciprocates vertically reciprocating needles is built-in.

FIG. 4 and FIG. 5 show a needle swinging device for such a conventional sewing machine. Inside the sewing machine main body 1, a needle bar drive mechanism driven by rotation of an upper shaft (not shown) is used. A needle bar 2 which is reciprocally moved up and down is provided, and a needle swing arm 3 formed in a substantially U-shape is attached to the needle bar 2 so as to support the vertical position of the needle bar 2. Has been. One end of a needle swinging shaft 4 is connected to the needle swinging arm 3, and the needle swinging shaft 4 is horizontally movable by a bearing body 5 provided upright on the inner lower surface of the sewing machine body 1. It is supported. Further, the other end of the needle swinging shaft 4 is connected to the tip end portion of the needle swinging drive link 6, and the base end portion of the needle swinging drive link 6 swings to the sewing machine main body 1. A tip end portion of a needle swing support link 8 rotatably supported is pivotally attached.

Further, below the inside of the sewing machine main body 1,
A horizontal cam drive shaft 9 extending in the front-rear direction of the sewing machine body 1 is provided, and a cam groove 10 having a desired shape is formed on one surface side at a rear end portion of the cam drive shaft 9. The needle swing cam 11 is fixed. This needle swing cam 11
The needle swing cam 11 is provided on the back surface of the sewing machine main body 1.
A side cover 12 is attached to cover the. A cam drive gear 13 is attached to the front end side of the cam drive shaft 9, and a transmission gear 14 is meshed with the cam drive gear 13. Further, a worm gear 15 that is meshed with a lower shaft (not shown) that is driven to rotate with the rotation of the upper shaft is coaxially attached to the transmission gear 14.
By rotating the lower shaft, the cam drive shaft 9 is rotated via the worm gear 15, the transmission gear 14, and the cam drive gear 13, so that the needle swing cam 11 is rotated.

A cam arm 16 is provided near the front side of the needle swinging cam 11, and a cam arm 16 is engaged with a cam groove 10 of the needle swinging cam 11 at the tip of the cam arm 16. The follower 17 is projected. A needle swing drive shaft 18 extending in the front-rear direction of the sewing machine body 1 is attached to a base end portion of the cam arm 16, and a cam follower 17 of the cam arm 16 is attached to a cam groove of the needle swing cam 11. By following along 10, the cam arm 16 is driven to swing, and the needle swing drive shaft 18 is rotated.

Further, a base end portion of a needle swinging drive arm 19 is fixed to a front end portion of the needle swinging drive shaft 18, and a tip end portion of the needle swinging drive arm 19 has the tip end portion thereof swung. A base end portion of a needle swing rod 7 connected to a middle portion of the drive link 6 is connected.

In such a conventional needle swinging device,
When the lower shaft is rotationally driven by the rotational drive of the upper shaft, the worm gear 15 is rotationally driven, and this rotational force is transmitted to the cam drive gear 13 via the transmission gear 14.
The cam drive shaft 9 is rotationally driven, and the needle swing cam 11 is rotationally driven. Then, the cam follower 17 follows the cam groove 10 rotated by the rotation of the needle swing cam 11, so that the cam arm 16 is swung, whereby the needle swing drive arm 19 is moved via the needle swing drive shaft 18. Is swung, and the needle swing rod 7 is vertically reciprocated. When the vertical movement of the needle swing rod 7 is transmitted to the needle swing drive link 6, the needle swing drive link 6 is moved in the horizontal direction by the swing motion of the needle swing support link 8.
The needle swing shaft 4 is moved in the axial direction, the needle bar 2 is horizontally moved via the needle swing arm 3, and the needle swing operation is performed, whereby a desired needle swing pattern such as zigzag stitching can be formed. It is possible.

FIG. 6 is a diagram showing an example of a stitch pattern of a zigzag stitch sewing machine. The zigzag stitch sewing machine 1 is a lock stitch sewing machine, and the upper thread is entangled with the lower thread to form a stitch each time the needle is moved up and down once. As a stitch pattern,
For example, each time the needle is moved up and down, the needle is alternately swung to the left or right to form a zigzag pattern of two-point zigzag, as shown in FIG. 6 (1).

Further, one vertical movement in the center of the zigzag results in three-point zigzag as shown in (2), and two vertical movements results in four-point zigzag as shown in (3). Other,
There is scallop sewing. As described above, the zigzag stitch sewing machine has a large elasticity and can perform wide stitches and pattern stitches.

Such a stitch pattern is determined by the left and right needle swing patterns with respect to the vertical movement of the needle, and the left and right needle swing patterns are determined by the cam 11.
When the upper shaft makes one rotation, the needle moves up and down once. Therefore, if a cam 11 that alternately swings the needle to the left and right is used every time the upper shaft makes one rotation, two-point zigzag results.

As described above, the stitch pattern is determined by the cam 11, and it is necessary to change the cam 11 to change the stitch pattern. However, in order to change the cam 11, it was necessary to remove the screw and replace the cam 11, and the stitch pattern could not be easily changed.

In view of the above problems, Japanese Patent Laid-Open No. 10-249079 discloses a zigzag stitch sewing machine capable of changing the stitch pattern by simply switching the cam. FIG. 7 is a plan view showing the structure of the cam device 20 of such a sewing machine.

The cam device 20 has first and second two cams 21 and 22, and a cam body 25. The first and second cams 21 and 22 are arranged facing each other with a space therebetween and rotate integrally. The cams 21 and 22 are grooved cams, and cam grooves are formed annularly on the surface. Cams 21,2
2 is arranged so that the cam grooves 26 and 27 face each other. The cam body 25 has first and second cam followers 23 and 24 corresponding to the first and second cams 21 and 22,
It is provided to be movable back and forth. Cam followers 23, 2
4 is arranged between the cams 21 and 22, and when the cam body 25 is moved backward, for example, the first cam follower 23 of the cam body 25 fits into the cam groove 26 of the first cam 21, and the needle swinging movement is performed. The mechanism 20 performs a needle swing motion according to the first cam 21.

On the contrary, when the cam body 25 is moved to the front,
The second cam follower 24 is the cam groove 2 of the second cam 22.
7, and the needle swinging motion is performed according to the second cam 22. In this way, the cam pattern can be easily changed and the stitch pattern can be easily changed only by moving the cam body 25.

Further, of the pair of cams 21 and 22, the second cam 22 arranged on the outer side can be replaced with another cam by removing the screw 28. Thereby, it is possible to change to three or more kinds of stitch patterns.

As a technique similar to this conventional cam device,
In addition, there is JP-A-8-117463.

[0017]

SUMMARY OF THE INVENTION The cam device 20 described above.
Then, a grooved cam is used as the cam. The grooved cam is an annular cam groove formed on the surface of the cam on the disc. The cam follower is fitted in the cam groove, and the inner surface or the outer surface of the cam groove functions as the cam surface.

In such a groove cam, it is necessary to form an annular cam groove on the surface as described above. That is, the outer diameter of the cam is larger than that of the cam surface. When the outer diameter of the cam becomes large, the sewing machine main body for accommodating the cam also has to be made large, and the entire sewing machine becomes large. In addition, this also increases the weight.

An object of the present invention is to provide a sewing machine in which the cams can be switched and at least one of which can be exchanged with the cam can be made compact and compact.

[0020]

According to a first aspect of the present invention, there is provided an upper shaft which rotates to drive a needle up and down, a cam which rotates in association with the rotation of the upper shaft, and a rotation of the cam. In the sewing machine including a needle swinging device that swings the vertically moving needle up and down, at least one of the cams is replaceable, and the needle swinging device comprises:
It is configured to be switchable to any of the cams by moving, and at least one of the plurality of cams is a rib cam having a rib protruding in the rotation axis direction of the cam over the entire outer peripheral portion of the cam, The needle swinging means is a sewing machine having a pair of cam followers sandwiching the rib of the rib cam.

The present invention according to claim 2 is characterized in that the plurality of cams is two, and both cams are the rib cams.

According to a third aspect of the present invention, the plurality of cams are two, one cam is the rib cam, and the other cam is a grooved cam having a cam groove. .

According to the invention, a rib cam is used as the cam of the needle swing mechanism. The rib cam is a cam having a rib on the outer periphery of the disc, and the rib is held by a pair of cam followers. That is, the inner surface and the outer surface of the rib function as a cam surface. In the prior art, since the grooved cam was used, the outer diameter of the cam was larger than the cam surface.
With rib cams, the outer diameter of the cam can be as large as the cam surface. That is, the diameter of the cam can be made smaller than that of the conventional technique, and the sewing machine can be made compact.

[0024]

1 is a front sectional view showing a structure of a zigzag stitch sewing machine 30 which is an embodiment of the present invention, and FIG. 2 is seen from a section line II-II in FIG. FIG. In these figures, the left-right direction is shown in FIG.
2 is the left-right direction, the up-down direction is the up-down direction on the paper surface of FIG. 1, and the front-back direction is the left-right direction on the paper surface of FIG.

An upper shaft 32 is arranged in a hollow sewing machine main body 31 along a sewing machine arm extending in the left-right direction, and is rotatably supported. A needle bar crank shaft 33 is attached to the left end of the upper shaft 32, and the needle bar crank shaft 33 is connected to a needle bar 34 via a needle bar crank rod 38 and a needle bar holder 37. A needle 35 is fixed to the lower end of the needle bar 34, and is supported by a needle bar frame 36 so as to be vertically movable. Therefore, when the upper shaft 32 is driven to rotate, the needle bar crankshaft 33 causes the needle 35 to move up and down together with the needle bar 34.

Next, the cam device 40 will be described.
The cam device 40 has a needle swing mechanism and a cam switching mechanism.
First, the needle swing mechanism will be described.

The needle swing mechanism includes a pair of cams 41 and 42,
Needle swinging means 43 is provided for moving the needle 35 that moves up and down following the rotation of the cam and swings it up and down. The cams 41 and 42 are
It rotates in synchronization with the upper shaft 32. The needle swing means 43 has a needle swing cam arm 45 having a cam follower, a needle swing drive rod 46, a needle bar yoke 47, and a needle bar frame shaft 48.

As for the cams 41 and 42, the cam 41 arranged at the rear side is a replaceable groove cam, and the cam 42 arranged at the front side is a fixed rib cam. The two cams 41 and 42 rotate integrally around the cam shaft 75.

The needle swing cam arm 45 includes a cam follower 50 for the groove cam 41, a cam follower 51 for the rib cam,
52, is supported so as to be movable in the front-rear direction, and switches to the groove cam 41 and the rib cam 42 by moving in the front-rear direction.

The needle swing cam arm 45 extends in the left-right direction, is rotatably supported on the sewing machine main body 31 by a needle swing drive shaft 62 provided at the left end portion, and cam followers 50 to 52 are provided at the right end portion. . Cam follower 50-5
2 moves up and down according to the cam surface of the cam 41 or the cam 42. That is, the needle swing cam arm 45 is connected to the cams 41, 4
According to the rotation of 2, with the needle swing drive shaft 62 as the center of rotation,
The right end moves up and down.

The needle swing drive arm 53 is connected to the needle swing cam arm 45 by a connecting shaft 64 and moves up and down together with the needle swing cam arm 45. A needle swing drive rod 46 is connected to the needle swing drive arm 53 via a connecting shaft 65. A long hole 54 is formed in the needle swing drive rod 46, and a cam shaft 75 is inserted through the long hole 54.
Are movably supported up and down. The upper end of the needle swing drive rod 46 is connected to the central portion of the needle bar yoke 47 by the connecting shaft 6.
It is rotatably connected via 6. The needle bar yoke 47 is
The center extends upward in the left-right direction so as to bend upward, and the right end is movably supported on the axis of the axis Z1 provided in the zigzag adjusting section Z.

A needle bar frame shaft 48 is connected to the left end of the needle bar yoke 47 via a needle bar yoke connector 61. The needle bar frame shaft 48 is supported by the sewing machine main body 31 so as to be movable in the left-right direction, and the left end portion thereof has the needle bar frame 36.
Connected to. With such a configuration, the cams 41, 4
When 2 rotates and the needle swing drive rod 46 moves up and down, the needle bar frame shaft 48 moves left and right through the needle bar yoke 47, whereby the needle bar 34 and the needle 35 can be swung left and right.

Next, the cam switching mechanism of the cam device 40 will be described. The groove cam 41 and the rib cam 42 have a cam shaft 75 in common and are arranged with a space. Groove cam 41
Has an annular cam groove 76 on the inner surface (the surface on the rib cam side) of the disk. The cam follower 50 for the grooved cam is arranged so as to face the cam groove 76. The rib cam 42 has a substantially cylindrical shape in which a rib 77 protruding in the rotation axis direction (cam axis direction) is formed on the entire outer peripheral portion of the disc. The rib cam cam followers 51 and 52 can sandwich the rib 77,
That is, the ribs 77 are attached to the needle swinging cam arm 45 with an interval substantially the same as the thickness of the ribs 77. The inner surface and the outer surface of the rib 77 function as a cam surface.

At the left end of the needle swing cam arm 45, a needle swing drive shaft 62 extending in the front-rear direction is inserted so as to be slidable forward and backward, and the switching slide shaft 82 causes the needle swing cam arm 45 to move forward and backward. You can slide it. The switching slide shaft 82 extends in the vertical direction and is supported by the sewing machine main body 31 so as to be rotatable around its axis. A switching lever 85 is fixed to the upper end portion, and a crank portion 83 is formed at the lower end portion. A rectangular parallelepiped rectangular piece 81 is rotatably connected to the crank portion 83.

A square piece guide portion 80 consisting of a pair of parallel plates is formed on the upper left end portion of the needle swing cam arm 45, and a square piece 81 is fitted therein. Therefore, when the switching lever 85 is operated to rotate the switching slide shaft 82, the square piece 81 moves back and forth via the crank portion 83, whereby
The needle swing cam arm 45 slides back and forth. When the needle swing cam arm 45 slides forward, the rib cam cam followers 51 and 52 sandwich the rib 77 of the rib cam 42 and switch to the rib cam 42, and when the needle swing cam arm 45 slides backward, the groove cam cam follower 50. Enters the groove 76 of the groove cam 41 and switches to the groove cam 41.

The rear side of the cam shaft 75 is supported by a wall portion 95 of the sewing machine main body 31 via a bush 96. The rib cam 42 is provided inside the wall portion 95 and the groove cam 41 is provided outside. As can be seen from the figure, the groove cam 41
Has a larger outer diameter than the rib cam 42. By arranging the rib cam 42 having a small outer diameter inside the wall portion 95,
The sewing machine body 31 can be made smaller. The groove cam 41 is
The groove cam 41 is fixed to the outside of the wall portion 95 by the screw 100 via the cam receiver 70. That is, by removing the screw 100, the outer groove cam 41 can be easily replaced. The outer groove cam 41 is usually covered with a cover or the like (not shown).

A cam worm wheel 90 is fixed to the cam shaft 75 via a cam receiver 92. Also, the upper shaft 32
An upper shaft gear 91 that meshes with the cam worm wheel 90 is fixed to. As a result, when the upper shaft 32 rotates, the cams 41 and 42 rotate.

Further, in this embodiment, the cam of the 2-point zigzag stitch pattern that is most frequently used is the replaceable groove cam 41, and the cam of the 4-point zigzag stitch pattern that is used next is the fixed-side rib cam 42. I am trying.

In the above-described embodiment, the fixed cam is the rib cam and the replaceable cam is the groove cam. However, the present invention is not limited to this, and the replaceable cam arranged on the outside as shown in FIG. The cam may also be the rib cam 42. With this structure, the structure of the entire sewing machine can be made more compact.

[0040]

As described above, according to the present invention, since the rib cam is used as the cam of the needle swing mechanism, the diameter of the cam can be made smaller than the prior art, the sewing machine can be made compact, and the weight of the sewing machine can be reduced. You can also plan.

[Brief description of drawings]

FIG. 1 is a zigzag stitch sewing machine 3 according to an embodiment of the present invention.
It is a front sectional view of No. 0.

FIG. 2 is a sectional view taken along the section line II-II in FIG.

FIG. 3 is a cross-sectional view showing a cam device having two rib cams 42.

FIG. 4 is a front sectional view of a conventional zigzag stitch sewing machine 1.

FIG. 5 is a side sectional view of the zigzag stitch sewing machine 1.

FIG. 6 is a diagram showing a stitch pattern of a zigzag stitch sewing machine.

FIG. 7 is a diagram showing a configuration of another conventional cam device 20.

[Explanation of symbols]

30 zigzag stitch sewing machine 31 sewing machine body 40 cam device 41 groove cam 42 rib cam

Claims (3)

[Claims] 1. An upper shaft that rotates to vertically move the needle up and down, a cam that rotates in conjunction with rotation of the upper shaft, and a needle that moves following the rotation of the cam and swings the vertically moving needle left and right. In a sewing machine including a swinging unit, a plurality of the cams are provided, at least one of which is replaceable, and the needle swinging unit is configured to be switchable to any one of the cams by moving the plurality of cams. At least one of them is a rib cam that has a rib that projects in the rotation axis direction of the cam over the entire outer peripheral portion of the cam, and the needle swinging means has a pair of cam followers that sandwich the rib of the rib cam. The characteristic sewing machine. 2. The sewing machine according to claim 1, wherein the plurality of cams are two, and both cams are the rib cams. 3. The sewing machine according to claim 1, wherein the plurality of cams are two, one cam is the rib cam, and the other cam is a grooved cam having a cam groove.